Certain chemical entities, compositions, and methods

ABSTRACT

Chemical entities that are bufalin derivatives, pharmaceutical compositions and methods of treatment of cancer are described.

This application claims the benefit of priority to U.S. ProvisionalApplication No. 61/295,177, filed Jan. 15, 2010, which is incorporatedherein by reference in its entirety.

Provided are certain chemical entities and compositions thereof that maybe useful in the treatment of cancer.

Cancer can be viewed as a breakdown in the communication between tumorcells and their environment, including their normal neighboring cells.Signals, both growth-stimulatory and growth-inhibitory, are routinelyexchanged between cells within a tissue. Normally, cells do not dividein the absence of stimulatory signals, and likewise, will cease dividingin the presence of inhibitory signals. In a cancerous, or neoplasticstate, a cell acquires the ability to “override” these signals and toproliferate under conditions in which normal cells would not grow.

Bufalin is one of the predominant components of bufodicnolides isolatedfrom traditional Chinese medicine (Chan'su, toad venom), and it has beenfound to be active against several cancer cell lines. Its anti-canceractivities in animal models have been reported. Its clinicalapplication, however, has been limited due to its poor solubility andnarrow therapeutic index.

Provided is at least one chemical entity chosen from compounds ofFormula I

and pharmaceutically acceptable salts thereof, wherein

Z is chosen from OR₉ and NR₁₀R₁₁; where

R₉ is chosen from optionally substituted alkyl, optionally substitutedcycloalkyl, optionally substituted heterocycloalkyl, optionallysubstituted aryl, and optionally substituted heteroaryl;

R₁₀ is chosen from hydrogen, optionally substituted alkyl, optionallysubstituted cycloalkyl, optionally substituted heterocycloalkyl,optionally substituted aryl, and optionally substituted heteroaryl;

R₁₁ is chosen from optionally substituted alkyl, optionally substitutedcycloalkyl, optionally substituted heterocycloalkyl, optionallysubstituted aryl, and optionally substituted heteroaryl;

or R₁₀ and R₁₁ may optionally be joined together with any interveningatoms to form an optionally substituted heterocycloalkyl ring.

Also provided is at least one chemical entity chosen from compounds ofFormula II

and pharmaceutically acceptable salts thereof, wherein

R₁ and R₂ are independently chosen from hydrogen, optionally substitutedalkyl, optionally substituted cycloalkyl, optionally substitutedheterocycloalkyl, optionally substituted aryl, and optionallysubstituted heteroaryl; or R₁ and R₂ may optionally be joined togetherwith any intervening atoms to form an optionally substitutedheterocycloalkyl ring;

for each occurrence, R₃ and R₄ are independently chosen from hydrogen,optionally substituted alkyl, optionally substituted cycloalkyl,optionally substituted heterocycloalkyl, optionally substituted aryl,and optionally substituted heteroaryl; or R₃ and R₄ may optionally bejoined together with any intervening atoms to form an optionallysubstituted cycloalkyl ring or optionally substituted heterocycloalkylring;

or R₁ and one occurrence of R₃ may optionally be joined together withany intervening atoms to form an optionally substituted heterocycloalkylring; and

n is selected from 1, 2, 3, 4, 5 and 6.

Also provided is at least one chemical entity chosen from compounds ofFormula III

and pharmaceutically acceptable salts thereof, wherein

R₅ is chosen from hydrogen, optionally substituted alkyl, optionallysubstituted cycloalkyl, optionally substituted heterocycloalkyl,optionally substituted aryl, and optionally substituted heteroaryl;

R₆ is chosen from optionally substituted alkyl, optionally substitutedcycloalkyl, optionally substituted heterocycloalkyl, optionallysubstituted aryl, optionally substituted heteroaryl, optionallysubstituted acyl, optionally substituted alkoxycarbonyl, and—P(═O)(OR₇)(OR₈), where R₇ and R₈ are independently chosen from hydrogenand optionally substituted alkyl.

Also provided is a pharmaceutical composition comprising apharmaceutically acceptable carrier and at least one chemical entitydescribed herein.

Also provided is a packaged pharmaceutical composition comprising apharmaceutical composition described herein and instructions for usingthe composition to treat a subject suffering from cancer.

Also provided is a method of treating cancer in a subject whichcomprises administering to a subject in need thereof a therapeuticallyeffective amount of at least one chemical entity described herein.

As used herein, the following words and phrases are generally intendedto have the meanings as set forth below, except to the extent that thecontext in which they are used indicates otherwise.

The following abbreviations and terms have the indicated meaningsthroughout:

-   AcOH=acetic acid-   Boc=tert-butoxycarbonyl-   c-=cyclo-   DCC=dicyclohexylcarbodiimide-   DIEA=N,N-diisopropylethylamine-   DMAP=4-dimethylaminopyridine-   EDC=1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-   eq=equivalent(s)-   Et=ethyl-   EtOAc or EA=ethyl acetate-   EtOH=ethanol-   g=gram-   h or hr=hour-   HBTU=O-(benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium    hexafluorophosphate-   HOBt=hydroxybenzotriazole-   HPLC=high pressure liquid chromatography-   i-=iso-   kg or Kg=kilogram-   L or l=liter-   LC/MS=LCMS=liquid chromatography-mass spectrometry-   LRMS=low resolution mass spectrometry-   m/z=mass-to-charge ratio-   Me=methyl-   MeOH=methanol-   mg=milligram-   min=minute-   mL=milliliter-   mmol=millimole-   n-=normal-   NaOAc=sodium acetate-   PE=petroleum ether-   Ph=phenyl-   Prep=preparative-   quant.=quantitative-   RP-HPLC=reverse phase-high pressure liquid chromatography-   rt or RT=room temperature-   s-=sec-=secondary-   t-=tert-=tertiary-   THF=tetrahydrofuran-   TLC=thin layer chromatography-   UV=ultraviolet

As used herein, when any variable occurs more than one time in achemical formula, its definition on each occurrence is independent ofits definition at every other occurrence.

As used herein, a dash (“-”) that is not between two letters or symbolsis used to indicate a point of attachment for a substituent. Forexample, —CONH₂ is attached through the carbon atom.

As used herein, “optional” or “optionally” is meant that thesubsequently described event or circumstance may or may not occur, andthat the description includes instances wherein the event orcircumstance occurs and instances in which it does not. For example,“optionally substituted alkyl” encompasses both “alkyl” and “substitutedalkyl” as defined below. It will be understood by those skilled in theart, with respect to any group containing one or more substituents, thatsuch groups are not intended to introduce any substitution orsubstitution patterns that are sterically impractical, syntheticallynon-feasible and/or inherently unstable.

As used herein, “alkyl” refers to straight chain and branched chainhaving the indicated number of carbon atoms, usually from 1 to 20 carbonatoms, for example 1 to 8 carbon atoms, such as 1 to 6 carbon atoms. Forexample C₁-C₆ alkyl encompasses both straight and branched chain alkylof from 1 to 6 carbon atoms. When an alkyl residue having a specificnumber of carbons is named, all branched and straight chain versionshaving that number of carbons are intended to be encompassed; thus, forexample, “butyl” is meant to include n-butyl, sec-butyl, isobutyl andt-butyl; “propyl” includes n-propyl and isopropyl. “Lower alkyl” refersto alkyl groups having one to six carbons. Examples of alkyl groupsinclude methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl,tert-butyl, pentyl, 2-pentyl, isopentyl, neopentyl, hexyl, 2-hexyl,3-hexyl, 3-methylpentyl, and the like. Alkylene is a subset of alkyl,referring to the same residues as alkyl, but having two points ofattachment. Alkylene groups will usually have from 2 to 20 carbon atoms,for example 2 to 8 carbon atoms, such as from 2 to 6 carbon atoms. Forexample, C₀ alkylene indicates a covalent bond and C₁ alkylene is amethylene group.

As used herein, “alkenyl” refers to an unsaturated branched orstraight-chain alkyl group having at least one carbon-carbon double bondderived by the removal of one molecule of hydrogen from adjacent carbonatoms of the parent alkyl. The group may be in either the cis or transconfiguration about the double bond(s). Typical alkenyl groups include,but are not limited to, ethenyl; propenyls such as prop-1-en-1-yl,prop-1-en-2-yl, prop-2-en-1-yl (allyl), prop-2-en-2-yl; butenyls such asbut-1-en-1-yl, but-1-en-2-yl, 2-methyl-prop-1-en-1-yl, but-2-en-1-yl,but-2-en-1-yl, but-2-en-2-yl, buta-1,3-dien-1-yl, buta-1,3-dien-2-yl;and the like. In certain embodiments, an alkenyl group has from 2 to 20carbon atoms and in other embodiments, from 2 to 6 carbon atoms. “Loweralkenyl” refers to alkenyl groups having two to six carbons.

As used herein, “alkynyl” refers to an unsaturated branched orstraight-chain alkyl group having at least one carbon-carbon triple bondderived by the removal of two molecules of hydrogen from adjacent carbonatoms of the parent alkyl. Typical alkynyl groups include, but are notlimited to, ethynyl; propynyls such as prop-1-yn-1-yl, prop-2-yn-1-yl;butynyls such as but-1-yn-1-yl, but-1-yn-3-yl, but-3-yn-1-yl; and thelike. In certain embodiments, an alkynyl group has from 2 to 20 carbonatoms and in other embodiments, from 3 to 6 carbon atoms. “Loweralkynyl” refers to alkynyl groups having two to six carbons.

As used herein, “cycloalkyl” refers to a non-aromatic carbo cyclic ring,usually having from 3 to 7 ring carbon atoms. The ring may be saturatedor have one or more carbon-carbon double bonds. Examples of cycloalkylgroups include cyclopropyl, cyclobutyl, cyclopentyl, cyclopentenyl,cyclohexyl, and cyclohexenyl, as well as bridged and caged ring groupssuch as norbornane.

As used herein, “alkoxy” refers to an alkyl group of the indicatednumber of carbon atoms attached through an oxygen bridge such as, forexample, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, sec-butoxy,tert-butoxy, pentyloxy, 2-pentyloxy, isopentyloxy, neopentyloxy,hexyloxy, 2-hexyloxy, 3-hexyloxy, 3-methylpentyloxy, and the like.Alkoxy groups will usually have from 1 to 7 carbon atoms attachedthrough the oxygen bridge. “Lower alkoxy” refers to alkoxy groups havingone to six carbons.

As used herein, “acyl” refers to the groups II-C(O)—; (alkyl)-C(O)—;(cycloalkyl)-C(O)—; (aryl)-C(O)—; (heteroaryl)-C(O)—; and(heterocycloalkyl)-C(O)—, wherein the group is attached to the parentstructure through the carbonyl functionality and wherein alkyl,cycloalkyl, aryl, heteroaryl, and heterocycloalkyl are as describedherein. Acyl groups have the indicated number of carbon atoms, with thecarbon of the keto group being included in the numbered carbon atoms.For example a C₂ acyl group is an acetyl group having the formulaCH₃(C═O)—.

As used herein, “formyl” refers to the group —C(O)H.

As used herein, “alkoxycarbonyl” refers to a group of the formula(alkoxy)(C═O)— attached through the carbonyl carbon wherein the alkoxygroup has the indicated number of carbon atoms. Thus a C₁-C₆alkoxycarbonyl group is an alkoxy group having from 1 to 6 carbon atomsattached through its oxygen to a carbonyl linker.

As used herein, “azido” refers to the group —N₃.

As used herein, “amino” refers to the group —NH₂.

As used herein, “mono- and di-(alkyl)amino” refers to secondary andtertiary alkyl amino groups, wherein the alkyl groups are as definedabove and have the indicated number of carbon atoms. The point ofattachment of the alkylamino group is on the nitrogen. Examples of mono-and di-alkylamino groups include ethylamino, dimethylamino, andmethyl-propyl-amino.

As used herein, “aminocarbonyl” refers to the group —CONR^(b)R^(c),where

R^(b) is chosen from H, optionally substituted C₁-C₆ alkyl, optionallysubstituted cycloalkyl, optionally substituted heterocycloalkyl,optionally substituted aryl, and optionally substituted heteroaryl,optionally substituted alkoxy; and

R^(c) is chosen from hydrogen and optionally substituted C₁-C₄ alkyl; or

R^(b) and R^(c) taken together with the nitrogen to which they arebound, form an optionally substituted 5- to 7-memberednitrogen-containing heterocycloalkyl which optionally includes 1 or 2additional heteroatoms chosen from O, N, and S in the heterocycloalkylring;

where each substituted group is independently substituted with one ormore substituents independently chosen from C₁-C₄ alkyl, aryl,heteroaryl, aryl-C₁-C₄ alkyl-, heteroaryl-C₁-C₄ alkyl-, C₁-C₄ haloalkyl,—OC₁-C₄ alkyl, —OC₁-C₄ alkylphenyl, —C₁-C₄ alkyl-OH, —OC₁-C₄ haloalkyl,halo, —OH, —C₁-C₄ alkyl-NH₂, —N(C₁-C₄ alkyl)(C₁-C₄ alkyl), —NH(C₁-C₄alkyl), —N(C₁-C₄ alkyl)(C₁-C₄ alkylphenyl), —NH(C₁-C₄ alkylphenyl),cyano, nitro, oxo (as a substituent for cycloalkyl, heterocycloalkyl, orheteroaryl), —CO₂H, —C(O)OC₁-C₄ alkyl, —CON(C₁-C₄ alkyl)(C₁-C₄ alkyl),—CONH(C₁-C₄ alkyl), —CONH₂, —NHC(O)(C₁-C₄ alkyl), —NHC(O)(phenyl),—N(C₁-C₄ alkyl)C(O)(C₁-C₄ alkyl), —N(C₁-C₄ alkyl)C(O)(phenyl),—C(O)C₁-C₄ alkyl, —C(O)C₁-C₄ alkylphenyl, —C(O)C₁-C₄ haloalkyl,—OC(O)C₁-C₄ alkyl, —SO₂(C₁-C₄ alkyl), —SO₂(phenyl), —SO₂(C₁-C₄haloalkyl), —SO₂NH₂, —SO₂NH(C₁-C₄ alkyl), —SO₂NH(phenyl), —NHSO₂(C₁-C₄alkyl), —NHSO₂(phenyl), and —NHSO₂(C₁-C₄ haloalkyl).

As used herein, “aryl” refers to: 6-membered carbocyclic aromatic rings,for example, benzene; bicyclic ring systems wherein at least one ring iscarbocyclic and aromatic, for example, naphthalene, indane, andtetralin; and tricyclic ring systems wherein at least one ring iscarbocyclic and aromatic, for example, fluorene.

For example, aryl includes 6-membered carbocyclic aromatic rings fusedto a 5- to 7-membered heterocycloalkyl ring containing 1 or moreheteroatoms chosen from N, O, and S. For such fused, bicyclic ringsystems wherein only one of the rings is a carbocyclic aromatic ring,the point of attachment may be at the carbocyclic aromatic ring or theheterocycloalkyl ring. Bivalent radicals formed from substituted benzenederivatives and having the free valences at ring atoms are named assubstituted phenylene radicals. Bivalent radicals derived from univalentpolycyclic hydrocarbon radicals whose names end in “-yl” by removal ofone hydrogen atom from the carbon atom with the free valence are namedby adding “-idene” to the name of the corresponding univalent radical,e.g. a naphthyl group with two points of attachment is termednaphthylidene. Aryl, however, does not encompass or overlap in any waywith heteroaryl, separately defined below. Hence, if one or morecarbocyclic aromatic rings is fused with a heterocycloalkyl aromaticring, the resulting ring system is heteroaryl, not aryl, as definedherein.

As used herein, “aryloxy” refers to the group —O-aryl.

As used herein, “aralkyl” refers to the group -alkyl-aryl.

As used herein, “carbamimidoyl” refers to the group —C(═NH)—NH2.

As used herein, “substituted carbamimidoyl” refers to the group—C(═NR^(c))—NR^(f)R^(g) where

R^(e) is chosen from hydrogen, cyano, optionally substituted alkyl,optionally substituted cycloalkyl, optionally substituted aryl,optionally substituted heteroaryl, and optionally substitutedheterocycloalkyl; and

R^(f) and R^(g) are independently chosen from hydrogen optionallysubstituted alkyl, optionally substituted cycloalkyl, optionallysubstituted aryl, optionally substituted heteroaryl, and optionallysubstituted heterocycloalkyl,

provided that at least one of R^(e), R^(f), and R^(g) is not hydrogenand wherein substituted alkyl, cycloalkyl, aryl, heterocycloalkyl, andheteroaryl refer respectively to alkyl, cycloalkyl, aryl,heterocycloalkyl, and heteroaryl wherein one or more (such as up to 5,for example, up to 3) hydrogen atoms are replaced by a substituentindependently chosen from

—R^(a), —OR^(b), optionally substituted amino (including —NR^(c)COR^(b),—NR^(c)CO₂R^(a), —NR^(c)CONR^(b)R^(c), —NR^(b)C(NR^(c))NR^(b)R^(c),—NR^(b)((NCN)NR^(b)R^(c), and —NR^(c)SO₂R^(a)), halo, cyano, nitro, oxo(as a substituent for cycloalkyl, heterocycloalkyl, and heteroaryl),optionally substituted acyl (such as —COR^(b)), optionally substitutedalkoxycarbonyl (such as —CO₂R^(b)), aminocarbonyl (such as—CONR^(b)R^(c)), —OCOR^(b), —OCO₂R^(a), —OCONR^(b)R^(c),—OP(O)(OR^(b))OR^(c), sulfanyl (such as SR^(b)), sulfinyl (such as—SOR^(a)), and sulfonyl (such as —SO₂R^(a) and —SO₂NR^(b)R^(c)),

where R^(a) is chosen from optionally substituted C1-C6 alkyl,optionally substituted aryl, and optionally substituted heteroaryl;

R^(b) is chosen from H, optionally substituted C1-C6 alkyl, optionallysubstituted aryl, and optionally substituted heteroaryl; and

R^(c) is chosen from hydrogen and optionally substituted C1-C4 alkyl; or

R^(b) and R^(c), and the nitrogen to which they are attached, form anoptionally substituted heterocycloalkyl group; and

where each optionally substituted group is unsubstituted orindependently substituted with one or more, such as one, two, or three,substituents independently chosen from C₁-C₄ alkyl, aryl, heteroaryl,aryl-C₁-C₄ alkyl-, heteroaryl-C₁-C₄ alkyl-, C₁-C₄ haloalkyl, —OC₁-C₄alkyl, —OC₁-C₄ alkylphenyl, —C₁-C₄ alkyl-OH, —OC₁-C₄ haloalkyl, halo,—OH, —NH₂, —C₁-C₄ alkyl-NH₂, —N(C₁-C₄ alkyl)(C₁-C₄ alkyl), —NH(C₁-C₄alkyl), —N(C₁-C₄ alkyl)(C₁-C4 alkylphenyl), —NH(C₁-C₄ alkylphenyl),cyano, nitro, oxo (as a substituent for cycloalkyl, heterocycloalkyl, orheteroaryl), —CO₂H, —C(O)OC₁-C₄ alkyl, —CON(C₁-C₄ alkyl)(C₁-C₄ alkyl),—CONH(C₁-C₄ alkyl), —CONH₂, —NHC(O)(C₁-C₄ alkyl), —NHC(O)(phenyl),—N(C₁-C₄ alkyl)C(O)(C₁-C₄ alkyl), —N(C₁-C₄ alkyl)C(O)(phenyl),—C(O)C₁-C₄ alkyl, —C(O)C₁-C₄ phenyl, —C(O)C₁-C₄ haloalkyl, —OC(O)C₁-C₄alkyl, —SO2(C₁-C₄ alkyl), —SO₂(phenyl), —SO₂(C₁-C₄ haloalkyl), —SO₂NH₂,—SO₂NH(C₁-C₄ alkyl), —SO₂NH(phenyl), —NHSO₂(C₁-C₄ alkyl),—NHSO₂(phenyl), and —NHSO₂(C₁-C₄ haloalkyl).

As used herein, “halo” refers to fluoro, chloro, bromo, and iodo, andthe term “halogen” includes fluorine, chlorine, bromine, and iodine.

As used herein, “haloalkyl” refers to alkyl as defined above having thespecified number of carbon atoms, substituted with 1 or more halogenatoms, up to the maximum allowable number of halogen atoms. Examples ofhaloalkyl include, but are not limited to, trifluoromethyl,difluoromethyl, 2-fluoroethyl, and penta-fluoroethyl.

As used herein, “heteroaryl” refers to:

5- to 7-membered aromatic, monocyclic rings containing one or more, forexample, from 1 to 4, or in certain embodiments, from 1 to 3,heteroatoms chosen from N, O, and S, with the remaining ring atoms beingcarbon;

bicyclic heterocycloalkyl rings containing one or more, for example,from 1 to 4, or in certain embodiments, from 1 to 3, heteroatoms chosenfrom N, O, and S, with the remaining ring atoms being carbon and whereinat least one heteroatom is present in an aromatic ring; and

tricyclic heterocycloalkyl rings containing one or more, for example,from 1 to 5, or in certain embodiments, from 1 to 4, heteroatoms chosenfrom N, O, and S, with the remaining ring atoms being carbon and whereinat least one heteroatom is present in an aromatic ring.

For example, heteroaryl includes a 5- to 7-membered heterocycloalkyl,aromatic ring fused to a 5- to 7-membered cycloalkyl or heterocycloalkylring. For such fused, bicyclic heteroaryl ring systems wherein only oneof the rings contains one or more heteroatoms, the point of attachmentmay be at either ring. When the total number of S and O atoms in theheteroaryl group exceeds 1, those heteroatoms are not adjacent to oneanother. In certain embodiments, the total number of S and O atoms inthe heteroaryl group is not more than 2. In certain embodiments, thetotal number of S and O atoms in the aromatic heterocycle is not morethan 1. Examples of heteroaryl groups include, but are not limited to,(as numbered from the linkage position assigned priority 1), 2-pyridyl,3-pyridyl, 4-pyridyl, 2,3-pyrazinyl, 3,4-pyrazinyl, 2,4-pyrimidinyl,3,5-pyrimidinyl, 2,3-pyrazolinyl, 2,4-imidazolinyl, isoxazolinyl,oxazolinyl, thiazolinyl, thiadiazolinyl, tetrazolyl, thienyl,benzothiophenyl, furanyl, benzofuranyl, benzoimidazolinyl, indolinyl,pyridazinyl, triazolyl, quinolinyl, pyrazolyl, and5,6,7,8-tetrahydroisoquinolinyl. Bivalent radicals derived fromunivalent heteroaryl radicals whose names end in “-yl” by removal of onehydrogen atom from the atom with the free valence are named by adding“-idene” to the name of the corresponding univalent radical, e.g. apyridyl group with two points of attachment is a pyridylidene.Heteroaryl does not encompass or overlap with aryl, cycloalkyl, orheterocycloalkyl, as defined herein

Substituted heteroaryl also includes ring systems substituted with oneor more oxide (—O⁻) substituents, such as pyridinyl N-oxides.

As used herein, “heterocycloalkyl” refers to a single, non-aromaticring, usually with 3 to 7 ring atoms, containing at least 2 carbon atomsin addition to 1-3 heteroatoms independently chosen from oxygen, sulfur,and nitrogen, as well as combinations comprising at least one of theforegoing heteroatoms. The ring may be saturated or have one or morecarbon-carbon double bonds. Suitable heterocycloalkyl groups include,for example (as numbered from the linkage position assigned priority 1),2-pyrrolidinyl, 2,4-imidazolidinyl, 2,3-pyrazolidinyl, 2-piperidyl,3-piperidyl, 4-piperidyl, and 2,5-piperizinyl. Morpholinyl groups arealso contemplated, including 2-morpholinyl and 3-morpholinyl (numberedwherein the oxygen is assigned priority 1). Substituted heterocycloalkylalso includes ring systems substituted with one or more oxo (═O) oroxide (—O⁻) substituents, such as piperidinyl N-oxide,morpholinyl-N-oxide, 1-oxo-1-thiomorpholinyl and1,1-dioxo-1-thiomorpholinyl.

“Heterocycloalkyl” also includes bicyclic ring systems wherein onenon-aromatic ring, usually with 3 to 7 ring atoms, contains at least 2carbon atoms in addition to 1-3 heteroatoms independently chosen fromoxygen, sulfur, and nitrogen, as well as combinations comprising atleast one of the foregoing heteroatoms; and the other ring, usually with3 to 7 ring atoms, optionally contains 1-3 heteratoms independentlychosen from oxygen, sulfur, and nitrogen and is not aromatic.

As used herein, “sulfanyl” refers to the groups: —S-(optionallysubstituted (C₁-C₆)alkyl), —S-(optionally substituted aryl),—S-(optionally substituted heteroaryl), and —S-(optionally substitutedheterocycloalkyl). Hence, sulfanyl includes the group C₁-C₆alkylsulfanyl.

As used herein, “sulfinyl” refers to the groups: —S(O)-(optionallysubstituted (C₁-C₆)alkyl), —S(O)-optionally substituted aryl),—S(O)-optionally substituted heteroaryl), —S(O)-(optionally substitutedheterocycloalkyl); and —S(O)-(optionally substituted amino).

As used herein, “sulfonyl” refers to the groups: —S(O₂)-(optionallysubstituted (C₁-C₆)alkyl), —S(O₂)-optionally substituted aryl),—S(O₂)-optionally substituted heteroaryl), —S(O₂)-(optionallysubstituted heterocycloalkyl), and —S(O₂)-(optionally substitutedamino).

As used herein, “substituted” refers to any one or more hydrogens on thedesignated atom or group is replaced with a selection from the indicatedgroup, provided that the designated atom's normal valence is notexceeded. When a substituent is oxo (i.e. ═O) then 2 hydrogens on theatom are replaced. Combinations of substituents and/or variables arepermissible only if such combinations result in stable compounds oruseful synthetic intermediates. A stable compound or stable structure ismeant to imply a compound that is sufficiently robust to surviveisolation from a reaction mixture, and subsequent formulation as anagent having at least practical utility. Unless otherwise specified,substituents are named into the core structure. For example, it is to beunderstood that when (cycloalkyl)alkyl is listed as a possiblesubstituent, the point of attachment of this substituent to the corestructure is in the alkyl portion.

As used herein, the terms “substituted” alkyl, cycloalkyl, aryl,heterocycloalkyl, and heteroaryl, unless otherwise expressly defined,refer respectively to alkyl, cycloalkyl, aryl, heterocycloalkyl, andheteroaryl wherein one or more (such as up to 5, for example, up to 3)hydrogen atoms are replaced by a substituent independently chosen from

—R^(a), —OR^(b), optionally substituted amino (including —NR^(c)COR^(b),—NR^(c)CO₂R^(a), —NR^(c)CONR^(b)R^(c), —NR^(b)C(NR^(c))NR^(b)R^(c),—NR^(b)C(NCN)NR^(b)R^(c), and —NR^(c)SO₂R^(a)), halo, cyano, azido,nitro, oxo (as a substituent for cycloalkyl or heterocycloalkyl),optionally substituted acyl (such as —COR^(b)), optionally substitutedalkoxycarbonyl (such as —CO₂R^(b)), aminocarbonyl (such as—CONR^(b)R^(c)), —OCOR^(b), —OCO₂R^(a), —OCONR^(b)R^(c),—OP(O)(OR^(b))OR^(c), sulfanyl (such as SR^(b)), sulfinyl (such as—SOR^(a)), and sulfonyl (such as —SO₂R^(a) and —SO₂NR^(b)R^(c)), where

R^(a) is chosen from optionally substituted C₁-C₆ alkyl, optionallysubstituted cycloalkyl, optionally substituted heterocycloalkyl,optionally substituted alkenyl, optionally substituted alkynyl,optionally substituted aryl, and optionally substituted heteroaryl;R^(b) is chosen from hydrogen, optionally substituted C₁-C₆ alkyl,optionally substituted cycloalkyl, optionally substitutedheterocycloalkyl, optionally substituted aryl, and optionallysubstituted heteroaryl; and

R_(c) is chosen from hydrogen and optionally substituted C₁-C₄ alkyl; or

R^(b) and R^(c), and the nitrogen to which they are attached, form anoptionally substituted heterocycloalkyl group; and

where each optionally substituted group is unsubstituted orindependently substituted with one or more, such as one, two, or three,substituents independently chosen from C₁-C₄ alkyl, aryl, heteroaryl,aryl-C₁-C₄ alkyl-, heteroaryl-C₁-C₄ alkyl-, C₁-C₄ haloalkyl, —OC₁-C₄alkyl, —OC₁-C₄ alkylphenyl, —C₁-C₄ alkyl-OH, —OC₁-C₄ haloalkyl, halo,—OH, —NH₂, —C₁-C₄ alkyl-NH₂, —N(C₁-C₄ alkyl)(C₁-C₄ alkyl), —NH(C₁-C₄alkyl), —N(C₁-C₄ alkyl)(C₁-C₄ alkylphenyl), —NH(C₁-C₄ alkylphenyl),cyano, nitro, oxo (as a substituent for cycloalkyl or heterocycloalkyl),—CO₂H, —C(O)OC₁-C₄ alkyl, —CON(C₁-C₄ alkyl)(C₁-C₄ alkyl), —CONH(C₁-C₄alkyl), —CONH₂, —NHC(O)(C₁-C₄ alkyl), —NHC(O)(phenyl), —N(C₁-C₄alkyl)C(O)(C₁-C₄ alkyl), —N(C₁-C₄ alkyl)C(O)(phenyl), —C(O)C₁-C₄ alkyl,—C(O)C₁-C₄ alkylphenyl, —C(O)C₁-C₄ haloalkyl, —OC(O)C₁-C₄ alkyl,—SO₂(C₁-C₄ alkyl), —SO₂(phenyl), —SO₂(C₁-C₄ haloalkyl), —SO₂NH₂,—SO₂NH(C₁-C₄ alkyl), —SO₂NH(phenyl), —NHSO₂(C₁-C₄ alkyl),—NHSO₂(phenyl), and —NHSO₂(C₁-C₄ haloalkyl).

As used herein, “substituted acyl” refers to the groups (substitutedalkyl)-C(O)—; (substituted cycloalkyl)-C(O)—; (substituted aryl)-C(O)—;(substituted heteroaryl)-C(O)—; and (substitutedheterocycloalkyl)-C(O)—, wherein the group is attached to the parentstructure through the carbonyl functionality and wherein substitutedalkyl, cycloalkyl, aryl, heteroaryl, and heterocycloalkyl, referrespectively to alkyl, cycloalkyl, aryl, heteroaryl, andheterocycloalkyl wherein one or more (such as up to 5, for example, upto 3) hydrogen atoms are replaced by a substituent independently chosenfrom

—R^(a), —OR^(b), optionally substituted amino (including —NR^(c)COR^(b),—NR^(c)CO₂R^(a), —NR^(c)CONR^(b)R^(c), —NR^(b)C(NR^(c))NR^(b)R^(c),—NR^(b)C(NCN)NR^(b)R^(c), and —NR^(c)SO₂R^(a)), halo, cyano, nitro, oxo(as a substituent for cycloalkyl or heterocycloalkyl), optionallysubstituted acyl (such as —COR^(b)), optionally substitutedalkoxycarbonyl (such as —CO₂R^(b)), aminocarbonyl (such as—CONR^(b)R^(c)), —OCOR^(b), —OCO₂R^(a), —OCONR^(b)R^(c),—OP(O)(OR^(b))OR^(c), sulfanyl (such as SR^(b)), sulfinyl (such as—SOR^(a)), and sulfonyl (such as —SO₂R^(a) and —SO₂NR^(b)R^(c)),

where R^(a) is chosen from optionally substituted C₁-C₆ alkyl,optionally substituted alkenyl, optionally substituted alkynyl,optionally substituted aryl, and optionally substituted heteroaryl;

R^(b) is chosen from H, optionally substituted C₁-C₆ alkyl, optionallysubstituted cycloalkyl, optionally substituted heterocycloalkyl,optionally substituted aryl, and optionally substituted heteroaryl; and

R^(c) is chosen from hydrogen and optionally substituted C₁-C₁ alkyl; or

R^(b) and R^(c), and the nitrogen to which they are attached, form anoptionally substituted heterocycloalkyl group; and

where each optionally substituted group is unsubstituted orindependently substituted with one or more, such as one, two, or three,substituents independently chosen from C₁-C₄ alkyl, aryl, heteroaryl,aryl-C₁-C₄ alkyl-, heteroaryl-C₁-C₄ alkyl-, C₁-C₄ haloalkyl, —OC₁-C₄alkyl, —OC₁-C₄ alkylphenyl, —C₁-C₄ alkyl-OH, —OC₁-C₄ haloalkyl, halo,—OH, —NH₂, —C₁-C₄ alkyl-NH₂, —N(C₁-C₄ alkyl)(C₁-C₄ alkyl), —NH(C₁-C₄alkyl), —N(C₁-C₄ alkyl)(C₁-C₄ alkylphenyl), —NH(C₁-C₄ alkylphenyl),cyano, nitro, oxo (as a substituent for cycloalkyl or heterocycloalkyl),—CO₂H, —C(O)OC₁-C₄ alkyl, —CON(C₁-C₄ alkyl)(C₁-C₄ alkyl), —CONH(C₁-C₄alkyl), —CONH₂, —NHC(O)(C₁-C₄ alkyl), —NHC(O)(phenyl), —N(C₁-C₄alkyl)C(O)(C₁-C₄ alkyl), —N(C₁-C₄ alkyl)C(O)(phenyl), —C(O)C₁-C₄ alkyl,—C(O)C₁-C₄ alkylphenyl, —C(O)C₁-C₄ haloalkyl, —OC(O)C₁-C₄ alkyl,—SO₂(C₁-C₄ alkyl), —SO₂(phenyl), —SO₂(C₁-C₄ haloalkyl), —SO₂NH₂,—SO₂NH(C₁-C₄ alkyl), —SO₂NH(phenyl), —NHSO₂(C₁-C₄ alkyl),—NHSO₂(phenyl), and —NHSO₂(C₁-C₄ haloalkyl).

As used herein, “substituted alkoxy” refers to alkoxy wherein the alkylconstituent is substituted (i.e. —O-(substituted alkyl)) wherein“substituted alkyl” refers to alkyl wherein one or more (such as up to5, for example, up to 3) hydrogen atoms are replaced by a substituentindependently chosen from

—R^(a), —OR^(b), optionally substituted amino (including —NR^(c)COR^(b),—NR^(c)CO₂R^(a), —NR^(c)CONR^(b)R^(c), —NR^(b)C(NR^(c))NR^(b)R^(c),—NR^(b)C(NCN)NR^(b)R^(c), and —NR^(c)SO₂R^(a)), halo, cyano, nitro, oxo(as a substituent for cycloalkyl or heterocycloalkyl), optionallysubstituted acyl (such as —COR^(b)), optionally substitutedalkoxycarbonyl (such as —CO₂R^(b)), aminocarbonyl (such as—CONR^(b)R^(c)), —OCOR^(b), —OCO₂R^(a), —OCONR^(b)R^(c),—OP(O)(OR^(b))OR^(c), sulfanyl (such as SR^(b)), sulfanyl (such as—SOR^(a)), and sulfonyl (such as —SO₂R^(a) and —SO₂NR^(b)R^(c)),

where R^(a) is chosen from optionally substituted C₁-C₆ alkyl,optionally substituted alkenyl, optionally substituted alkynyl,optionally substituted aryl, and optionally substituted heteroaryl;

R^(b) is chosen from H, optionally substituted C₁-C₆ alkyl, optionallysubstituted cycloalkyl, optionally substituted heterocycloalkyl,optionally substituted aryl, and optionally substituted heteroaryl; and

R^(c) is chosen from hydrogen and optionally substituted C₁-C₄ alkyl; or

R^(b) and R^(c), and the nitrogen to which they are attached, form anoptionally substituted heterocycloalkyl group; and

where each optionally substituted group is unsubstituted orindependently substituted with one or more, such as one, two, or three,substituents independently chosen from C₁-C₁ alkyl, aryl, heteroaryl,aryl-C₁-C₄ alkyl-, heteroaryl-C₁-C₄ alkyl-, C₁-C₄ haloalkyl, —OC₁-C₄alkyl, —OC₁-C₄ alkylphenyl, —C₁-C₄ alkyl-OH, —OC₁-C₄ haloalkyl, halo,—OH, —NH₂, —C₁-C₄ alkyl-NH₂, —N(C₁-C₄ alkyl)(C₁-C₄ alkyl), —NH(C₁-C₄alkyl), —N(C₁-C₄ alkyl)(C₁-C₄ alkylphenyl), —NH(C₁-C₄ alkylphenyl),cyano, nitro, oxo (as a substituent for cycloalkyl or heterocycloalkyl),—CO₂H, —C(O)OC₁-C₄ alkyl, —CON(C₁-C₄ alkyl)(C₁-C₄ alkyl), —CONH(C₁-C₄alkyl), —CONH₂, —NHC(O)(C₁-C₄ alkyl), —NHC(O)(phenyl), —N(C₁-C₄alkyl)C(O)(C₁-C₄ alkyl), —N(C₁-C₄ alkyl)C(O)(phenyl), —C(O)C₁-C₄ alkyl,—C(O)C₁-C₄ alkylphenyl, —C(O)C₁-C₄ haloalkyl, —OC(O)C₁-C₄ alkyl,—SO₂(C₁-C₄ alkyl), —SO₂(phenyl), —SO₂(C₁-C₄ haloalkyl), —SO₂NH₂,—SO₂NH(C₁-C₄ alkyl), —SO₂NH(phenyl), —NHSO₂(C₁-C₄ alkyl),—NHSO₂(phenyl), and —NHSO₂(C₁-C₄ haloalkyl).

In some embodiments, a substituted alkoxy group is “polyalkoxy” or—O-(optionally substituted alkylene)-(optionally substituted alkoxy),and includes groups such as —OCH₂CH₂OCH₃, and residues of glycol etherssuch as polyethyleneglycol, and —O(CH₂CH₂O)_(x)CH₃, where x is aninteger of 2-20, such as 2-10, and for example, 2-5. Another substitutedalkoxy group is hydroxyalkoxy or —OCH₂(CH₂)_(y)OH, where y is an integerof 1-10, such as 1-4.

As used herein, “substituted alkoxycarbonyl” refers to the group(substituted alkyl)-O—C(O)— wherein the group is attached to the parentstructure through the carbonyl functionality and wherein substitutedrefers to alkyl wherein one or more (such as up to 5, for example, up to3) hydrogen atoms are replaced by a substituent independently chosenfrom

—R^(a), —OR^(b), optionally substituted amino (including —NR^(c)COR^(b),—NR^(c)CO₂R^(a), —NR^(c)CONR^(b)R^(c), —NR^(b)C(NR^(c))NR^(b)R^(c),—NR^(b)C(NCN)NR^(b)R^(c), and —NR^(c)SO₂R^(a)), halo, cyano, nitro, oxo(as a substituent for cycloalkyl or heterocycloalkyl), optionallysubstituted acyl (such as —COR^(b)), optionally substitutedalkoxycarbonyl (such as —CO₂R^(b)), aminocarbonyl (such as—CONR^(b)R^(c)), —OCOR^(b), —OCO₂R^(a), —OCONR^(b)R^(c),—OP(O)(OR^(b))OR^(c), sulfanyl (such as SR^(b)), sulfanyl (such as—SOR^(a)), and sulfonyl (such as —SO₂R^(a) and —SO₂NR^(b)R^(c)),

where R^(a) is chosen from optionally substituted C₁-C₆ alkyl,optionally substituted alkenyl, optionally substituted alkynyl,optionally substituted aryl, and optionally substituted heteroaryl;

R^(b) is chosen from H, optionally substituted C₁-C₆ alkyl, optionallysubstituted cycloalkyl, optionally substituted heterocycloalkyl,optionally substituted aryl, and optionally substituted heteroaryl; and

R^(c) is chosen from hydrogen and optionally substituted C₁-C₄ alkyl; or

R^(b) and R^(c), and the nitrogen to which they are attached, form anoptionally substituted heterocycloalkyl group; and

where each optionally substituted group is unsubstituted orindependently substituted with one or more, such as one, two, or three,substituents independently chosen from C₁-C₄ alkyl, aryl, heteroaryl,aryl-C₁-C₄ alkyl-, heteroaryl-C₁-C₄ alkyl-, C₁-C₄ haloalkyl, —OC₁-C₄alkyl, —OC₁-C₄ alkylphenyl, —C₁-C₄ alkyl-OH, —OC₁-C₄ haloalkyl, halo,—OH, —NH₂, —C₁-C₄ alkyl-NH₂, —N(C₁-C₄ alkyl)(C₁-C₄ alkyl), —NH(C₁-C₄alkyl), —N(C₁-C₄ alkyl)(C₁-C₄ alkylphenyl), —NH(C₁-C₄ alkylphenyl),cyano, nitro, oxo (as a substituent for cycloalkyl or heterocycloalkyl),—CO₂H, —C(O)OC₁-C₄ alkyl, —CON(C₁-C₄ alkyl)(C₁-C₄ alkyl), —CONH(C₁-C₄alkyl), —CONH₂, —NHC(O)(C₁-C₄ alkyl), —NHC(O)(phenyl), —N(C₁-C₄alkyl)C(O)(C₁-C₄ alkyl), —N(C₁-C₄ alkyl)C(O)(phenyl), —C(O)C₁-C₄ alkyl,—C(O)C₁-C₄ alkylphenyl, —C(O)C₁-C₄ haloalkyl, —OC(O)C₁-C₄ alkyl,—SO₂(C₁-C₄ alkyl), —SO₂(phenyl), —SO₂(C₁-C₄ haloalkyl), —SO₂NH₂,—SO₂NH(C₁-C₄ alkyl), —SO₂NH(phenyl), —NHSO₂(C₁-C₄ alkyl),—NHSO₂(phenyl), and —NHSO₂(C₁-C₄ haloalkyl).

As used herein, “substituted amino” refers to the group —NHR^(d) or—NR^(d)R^(c) wherein R^(d) is chosen from hydroxy, formyl, optionallysubstituted alkoxy, optionally substituted alkyl, optionally substitutedcycloalkyl, optionally substituted acyl, optionally substitutedcarbamimidoyl, aminocarbonyl, optionally substituted aryl, optionallysubstituted heteroaryl, optionally substituted heterocycloalkyl,optionally substituted alkoxycarbonyl, sulfinyl and sulfonyl, andwherein R^(c) is chosen from optionally substituted alkyl, optionallysubstituted cycloalkyl, optionally substituted aryl, optionallysubstituted heteroaryl, and optionally substituted heterocycloalkyl, andwherein substituted alkyl, cycloalkyl, aryl, heterocycloalkyl, andheteroaryl refer respectively to alkyl, cycloalkyl, aryl,heterocycloalkyl, and heteroaryl wherein one or more (such as up to 5,for example, up to 3) hydrogen atoms are replaced by a substituentindependently chosen from

—R^(a), —OR^(b), optionally substituted amino (including —NR^(c)COR^(b),—NR^(c)CO₂R^(a), —NR^(c)CONR^(b)R^(c), —NR^(b)C(NR^(c))NR^(b)R^(c),—NR^(b)C(NCN)NR^(b)R^(c), and —NR^(c)SO₂R^(a)), halo, cyano, nitro, oxo(as a substituent for cycloalkyl or heterocycloalkyl), optionallysubstituted acyl (such as —COR^(b)), optionally substitutedalkoxycarbonyl (such as —CO₂R^(b)), aminocarbonyl (such as—CONR^(b)R^(c)), —OCOR^(b), —OCO₂R^(a), —OCONR^(b)R^(c),—OP(O)(OR^(b))OR^(c), sulfanyl (such as SR^(b)), sulfinyl (such as—SOR^(a)), and sulfonyl (such as —SO₂R^(a) and —SO₂NR^(b)R^(c)),

where R^(a) is chosen from optionally substituted C₁-C₆ alkyl,optionally substituted alkenyl, optionally substituted alkynyl,optionally substituted aryl, and optionally substituted heteroaryl;

R^(b) is chosen from H, optionally substituted C₁-C₆ alkyl, optionallysubstituted cycloalkyl, optionally substituted heterocycloalkyl,optionally substituted aryl, and optionally substituted heteroaryl; and

R^(c) is chosen from hydrogen and optionally substituted C₁-C₄ alkyl; or

R^(b) and R^(c), and the nitrogen to which they are attached, form anoptionally substituted heterocycloalkyl group; and

where each optionally substituted group is unsubstituted orindependently substituted with one or more, such as one, two, or three,substituents independently chosen from C₁-C₄ alkyl, aryl, heteroaryl,aryl-C₁-C₄ alkyl-, heteroaryl-C₁-C₄ alkyl-, C₁-C₄ haloalkyl, —OC₁-C₄alkyl, —OC₁-C₄ alkylphenyl, —C₁-C₄ alkyl-OH, —OC₁-C₄ haloalkyl, halo,—OH, —NH₂, —C₁-C₄ alkyl-NH₂, —N(C₁-C₄ alkyl)(C_(j)—C₄ alkyl), —NH(C₁-C₄alkyl), —N(C₁-C₄ alkyl)(C₁-C₄ alkylphenyl), —NH(C₁-C₄ alkylphenyl),cyano, nitro, oxo (as a substituent for cycloalkyl or heterocycloalkyl),—CO₂H, —C(O)OC₁-C₄ alkyl, —CON(C₁-C₄ alkyl)(C₁-C₄ alkyl), —CONH(C₁-C₄alkyl), —CONH₂, —NHC(O)(C₁-C₄ alkyl), —NHC(O)(phenyl), —N(C₁-C₄alkyl)C(O)(C₁-C₄ alkyl), —N(C₁-C₄ alkyl)C(O)(phenyl), —C(O)C₁-C₄ alkyl,—C(O)C₁-C₄ alkylphenyl, —C(O)C₁-C₄ haloalkyl, —OC(O)C₁-C₄ alkyl,—SO₂(C₁-C₄ alkyl), —SO₂(phenyl), —SO₂(C₁-C₄ haloalkyl), —SO₂NH₂,—SO₂NH(C₁-C₄ alkyl), —SO₂NH(phenyl), —NHSO₂(C₁-C₄ alkyl),—NHSO₂(phenyl), and —NHSO₂(C₁-C₄ haloalkyl); and

wherein optionally substituted acyl, optionally substitutedalkoxycarbonyl, sulfinyl and sulfonyl are as defined herein.

The term “substituted amino” also refers to N-oxides of the groups—NHR^(d), and NR^(d)R^(d) each as described above. N-oxides can beprepared by treatment of the corresponding amino group with, forexample, hydrogen peroxide or m-chloroperoxybenzoic acid. The personskilled in the art is familiar with reaction conditions for carrying outthe N-oxidation.

Compounds described herein include, but are not limited to, theiroptical isomers, racemates, and other mixtures thereof. In thosesituations, the single enantiomers or diastereomers, i.e., opticallyactive forms, can be obtained by asymmetric synthesis or by resolutionof the racemates. Resolution of the racemates can be accomplished, forexample, by conventional methods such as crystallization in the presenceof a resolving agent, or chromatography, using, for example a chiralhigh-pressure liquid chromatography (HPLC) column. In addition,compounds include Z- and E-forms (or cis- and trans-forms) of compoundswith carbon-carbon double bonds. Where compounds described herein existin various tautomeric forms, the term “compound” is intended to includeall tautomeric forms of the compound.

Compounds of Formula I-III also include crystalline and amorphous formsof those compounds, including, for example, polymorphs,pseudopolymorphs, solvates (including hydrates), unsolvated polymorphs(including anhydrates), conformational polymorphs, and amorphous formsof the compounds, as well as mixtures thereof “Crystalline form,”“polymorph,” and “novel form” may be used interchangeably herein, andare meant to include all crystalline and amorphous forms of thecompound, including, for example, polymorphs, pseudopolymorphs, solvates(including hydrates), unsolvated polymorphs (including anhydrates),conformational polymorphs, and amorphous forms, as well as mixturesthereof, unless a particular crystalline or amorphous form is referredto. Similarly, “pharmaceutically acceptable salts of compounds ofFormula I-III also include crystalline and amorphous forms of thosecompounds, including, for example, polymorphs, pseudopolymorphs,solvates (including hydrates), unsolvated polymorphs (includinganhydrates), conformational polymorphs, and amorphous forms of thepharmaceutically acceptable salts, as well as mixtures thereof.

A “solvate” is formed by the interaction of a solvent and a compound.The term “compound” is intended to include solvates of compounds.Similarly, “pharmaceutically acceptable salts” includes solvates ofpharmaceutically acceptable salts. Suitable solvates arepharmaceutically acceptable solvates, such as hydrates, includingmonohydrates and hemi-hydrates.

Compounds of Formula I-III also include other pharmaceuticallyacceptable forms of the recited compounds, including chelates,non-covalent complexes, prodrugs, and mixtures thereof.

A “chelate” is formed by the coordination of a compound to a metal ionat two (or more) points. The term “compound” is intended to includechelates of compounds. Similarly, “pharmaceutically acceptable salts”includes chelates of pharmaceutically acceptable salts.

A “non-covalent complex” is formed by the interaction of a compound andanother molecule wherein a covalent bond is not formed between thecompound and the molecule. For example, complexation can occur throughvan der Waals interactions, hydrogen bonding, and electrostaticinteractions (also cal led ionic bonding). Such non-covalent complexesare included in the term “compound’. Similarly, “pharmaceuticallyacceptable salts” includes “non-covalent complexes” of pharmaceuticallyacceptable salts.

The term “hydrogen bond” refers to a form of association between anelectronegative atom (also known as a hydrogen bond acceptor) and ahydrogen atom attached to a second, relatively electronegative atom(also known as a hydrogen bond donor). Suitable hydrogen bond donor andacceptors are well understood in medicinal chemistry.

“Hydrogen bond acceptor” refers to a group comprising an oxygen ornitrogen, such as an oxygen or nitrogen that is sp²-hybridized, an etheroxygen, or the oxygen of a sulfoxide or N-oxide.

The term “hydrogen bond donor” refers to an oxygen, nitrogen, orheteroaromatic carbon that bears a hydrogen.group containing a ringnitrogen or a heteroaryl group containing a ring nitrogen.

The compounds disclosed herein can be used in different enrichedisotopic forms, e.g., enriched in the content of ²H, ³H, ¹¹C, ¹³C and/or¹⁴C. In one particular embodiment, the compound is deuterated at atleast one position. Such deuterated forms can be made by the proceduredescribed in U.S. Pat. Nos. 5,846,514 and 6,334,997. As described inU.S. Pat. Nos. 5,846,514 and 6,334,997, deuteration can improve theefficacy and increase the duration of action of drugs.

Deuterium substituted compounds can be synthesized using various methodssuch as described in: Dean, Dennis C.; Editor. Recent Advances in theSynthesis and Applications of Radiolabeled Compounds for Drug Discoveryand Development. [In: Curr., Pharm. Des., 2000; 6(10)] 2000, 110 pp;George W.; Varma, Rajender S. The Synthesis of Radiolabeled Compoundsvia Organometallic Intermediates, Tetrahedron, 1989, 45(21), 6601-21;and Evans, E. Anthony. Synthesis of radiolabeled compounds, J.Radioanal. Chem., 1981, 64(1-2), 9-32.

“Pharmaceutically acceptable salts” include, but are not limited tosalts with inorganic acids, such as hydrochlorate, phosphate,diphosphate, hydrobromate, sulfate, sulfinate, nitrate, and like salts;as well as salts with an organic acid, such as malate, maleate,fumarate, tartrate, succinate, citrate, acetate, lactate,methanesulfonate, p-toluenesulfonate, 2-hydroxyethylsulfonate, benzoate,salicylate, stearate, and alkanoate such as acetate, HOOC—(CH₂)_(n)—COOHwhere n is 0-4, and like salts. Similarly, pharmaceutically acceptablecations include, but are not limited to sodium, potassium, calcium,aluminum, lithium, and ammonium.

In addition, if the compounds described herein are obtained as an acidaddition salt, the free base can be obtained by basifying a solution ofthe acid salt. Conversely, if the product is a free base, an additionsalt, particularly a pharmaceutically acceptable addition salt, may beproduced by dissolving the free base in a suitable organic solvent andtreating the solution with an acid, in accordance with conventionalprocedures for preparing acid addition salts from base compounds. Thoseskilled in the art will recognize various synthetic methodologies thatmay be used to prepare non-toxic pharmaceutically acceptable additionsalts.

“Prodrugs” described herein include any compound that becomes a compoundof Formula I when administered to a subject, e.g., upon metabolicprocessing of the prodrug. Similarly, “pharmaceutically acceptablesalts” includes “prodrugs” of pharmaceutically acceptable salts.Examples of prodrugs include derivatives of functional groups, such as acarboxylic acid group, in the compounds of Formula I. Exemplary prodrugsof a carboxylic acid group include, but are not limited to, carboxylicacid esters such as alkyl esters, hydroxyalkyl esters, arylalkyl esters,and aryloxyalkyl esters. Other exemplary prodrugs include lower alkylesters such as ethyl ester, acyloxyalkyl esters such aspivaloyloxymethyl (POM), glycosides, and ascorbic acid derivatives.

Other exemplary prodrugs include amides of carboxylic acids. Exemplaryamide prodrugs include metabolically labile amides that are formed, forexample, with an amine and a carboxylic acid. Exemplary amines includeNH₂, primary, and secondary amines such as NHR^(x), and NR^(x)R^(y),wherein R^(x) is hydrogen, (C₁-C₁₈)-alkyl, (C₃-C₇)-cycloalkyl,(C₃-C₇)-cycloalkyl-(C₁-C₄)-alkyl-, (C₆-C₁₄)-aryl which is unsubstitutedor substituted by a residue (C₁-C₂)-alkyl, (C₁-C₂)-alkoxy, fluoro, orchloro; heteroaryl-, (C₆-C₁₄)-aryl-(C₁-C₄)-alkyl- where aryl isunsubstituted or substituted by a residue (C₁-C₂)-alkyl, (C₁-C₂)-alkoxy,fluoro, or chloro; or heteroaryl-(C₁-C₄)-alkyl- and in which R^(y) hasthe meanings indicated for R^(x) with the exception of hydrogen orwherein R^(x) and R^(y), together with the nitrogen to which they arehound, form an optionally substituted 4- to 7-membered heterocycloalkylring which optionally includes one or two additional heteroatoms chosenfrom nitrogen, oxygen, and sulfur. A discussion of prodrugs is providedin T. Higuchi and V. Stella, Pro-drugs as Novel Delivery Systems, Vol.14 of the A.C.S. Symposium Series, in Edward B. Roche, ed.,Bioreversible Carriers in Drug Design, American PharmaceuticalAssociation and Pergamon Press, 1987, and in Design of Prodrugs, ed. H.Bundgaard, Elsevier, 1985.

As used herein the terms “group”, “radical” or “fragment” are synonymousand are intended to indicate functional groups or fragments of moleculesattachable to a bond or other fragments of molecules.

As used herein, “modulation” refers to a change in activity as a director indirect response to the presence of a chemical entity as describedherein, relative to the activity of in the absence of the chemicalentity. The change may be an increase in activity or a decrease inactivity, and may be due to the direct interaction of the compound withthe a target or due to the interaction of the compound with one or moreother factors that in turn affect the target's activity. For example,the presence of the chemical entity may, for example, increase ordecrease the target activity by directly binding to the target, bycausing (directly or indirectly) another factor to increase or decreasethe target activity, or by (directly or indirectly) increasing ordecreasing the amount of target present in the cell or organism.

As used herein, “active agent” is used to indicate a chemical entitywhich has biological activity. In certain embodiments, an “active agent”is a compound having pharmaceutical utility. For example an active agentmay be an anti-cancer therapeutic.

As used herein, “significant” refers to any detectable change that isstatistically significant in a standard parametric test of statisticalsignificance such as Student's T-test, where p<0.05.

As used herein, a “pharmaceutically acceptable” component is one that issuitable for use with humans and/or animals without undue adverse sideeffects (such as toxicity, irritation, and allergic response)commensurate with a reasonable benefit/risk ratio.

As used herein, “therapeutically effective amount” of a chemical entitydescribed herein refers to an amount effective, when administered to ahuman or non-human subject, to provide a therapeutic benefit such asamelioration of symptoms, slowing of disease progression, or preventionof disease.

“Treating” or “treatment” encompasses administration of at least onecompound of Formula I-III, or a pharmaceutically acceptable saltthereof, to a mammalian subject, particularly a human subject, in needof such an administration and includes (i) arresting the development ofclinical symptoms of the disease, such as cancer, (ii) bringing about aregression in the clinical symptoms of the disease, such as cancer,and/or (iii) prophylactic treatment for preventing the onset of thedisease, such as cancer.

As used herein, “cancer” refers to all types of cancer or neoplasm ormalignant tumors found in mammals, including carcinomas and sarcomas.Examples of cancer are cancer of the brain, breast, cervix, colon, head& neck, kidney, lung, non-small cell lung, melanoma, mesothelioma,ovary, sarcoma, stomach, uterus and Medulloblastoma.

As used herein, “subject” refers to a mammal that has been or will bethe object of treatment, observation or experiment. The methodsdescribed herein can be useful in both human therapy and veterinaryapplications. In some embodiments, the subject is a human.

The term “mammal” is intended to have its standard meaning, andencompasses humans, dogs, cats, sheep, and cows, for example.

Provided is at least one chemical entity chosen from compounds ofFormula

and pharmaceutically acceptable salts thereof, wherein

Z is chosen from OR₉ and NR₁₀R₁₁; where

R₉ is chosen from optionally substituted alkyl, optionally substitutedcycloalkyl, optionally substituted heterocycloalkyl, optionallysubstituted aryl, and optionally substituted heteroaryl;

R₁₀ is chosen from hydrogen, optionally substituted alkyl, optionallysubstituted cycloalkyl, optionally substituted heterocycloalkyl,optionally substituted aryl, and optionally substituted heteroaryl;

R₁₁ is chosen from optionally substituted alkyl, optionally substitutedcycloalkyl, optionally substituted heterocycloalkyl, optionallysubstituted aryl, and optionally substituted heteroaryl;

or R₁₀ and R₁₁ may optionally be joined together with any interveningatoms to form an optionally substituted heterocycloalkyl ring.

In some embodiments, Z is OR, In some embodiments, R₉ is chosen fromoptionally substituted alkyl, optionally substituted cycloalkyl, andoptionally substituted heterocycloalkyl

In some embodiments, Z is NR₁₀R₁₁. In some embodiments, R₁₀ is chosenfrom hydrogen, optionally substituted alkyl, optionally substitutedcycloalkyl, and optionally substituted heterocycloalkyl, and R₁₁ ischosen from optionally substituted alkyl, optionally substitutedcycloalkyl, and optionally substituted heterocycloalkyl. In someembodiments, R₁₀ is hydrogen and R₁₁ is optionally substituted alkyl. Insome embodiments, R₁₀ is hydrogen and R₁₁ is alkyl. In some embodiments,R₁₀ and R₁₁ are joined together to form a 5- to 7-memberedheterocycloalkyl ring.

In some embodiments, the compound of Formula I is chosen from compoundsI-a-I-f.

Also provided is at least one chemical entity chosen from compounds ofFormula II

and pharmaceutically acceptable salts thereof, wherein

R₁ and R₂ are independently chosen from hydrogen, optionally substitutedalkyl, optionally substituted cycloalkyl, optionally substitutedheterocycloalkyl, optionally substituted aryl, and optionallysubstituted heteroaryl; or R₁ and R₂ may optionally be joined togetherwith any intervening atoms to form an optionally substitutedheterocycloalkyl ring;

for each occurrence, R₃ and R₄ are independently chosen from hydrogen,optionally substituted alkyl, optionally substituted cycloalkyl,optionally substituted heterocycloalkyl, optionally substituted aryl,and optionally substituted heteroaryl; or R₁ and R₄ may optionally bejoined together with any intervening atoms to form an optionallysubstituted cycloalkyl ring or optionally substituted heterocycloalkylring;

or R₁ and one occurrence of R₃ may optionally be joined together withany intervening atoms to form an optionally substituted heterocycloalkylring; and

n is selected from 1, 2, 3, 4, 5 and 6.

In some embodiments, R₁ and R₂ are each independently chosen fromhydrogen and optionally substituted lower alkyl. In some embodiments, R₁and R₂ are both hydrogen.

In some embodiments, R₁ and R₂ are joined together to form a 5- to7-membered heterocycloalkyl ring.

In some embodiments, R₃ and R₄ are each independently chosen fromhydrogen and optionally substituted lower alkyl.

In some embodiments, n is chosen from 1, 2, and 3.

In some embodiments, n is 1, and R₁ and R₃ are joined together to form a5- to 7-membered heterocycloalkyl ring.

In some embodiments, the compound of Formula II is chosen from compoundsII-a-II-d.

In some embodiments, the compound of Formula II is chosen from compoundsII-e-II-h.

Also provided is at least one chemical entity chosen from compounds ofFormula III

and pharmaceutically acceptable salts thereof, wherein

R₅ is chosen from hydrogen, optionally substituted alkyl, optionallysubstituted cycloalkyl, optionally substituted heterocycloalkyl,optionally substituted aryl, and optionally substituted heteroaryl;

R₆ is chosen from optionally substituted alkyl, optionally substitutedcycloalkyl, optionally substituted heterocycloalkyl, optionallysubstituted aryl, optionally substituted heteroaryl, optionallysubstituted acyl, optionally substituted alkoxycarbonyl, and—P(═O)(OR₇)(OR₈), where R₇ and R₈ are independently chosen from hydrogenand optionally substituted alkyl.

In some embodiments, R₅ is chosen from hydrogen and optionallysubstituted lower alkyl. In some embodiments, R₅ is chosen from hydrogenand lower alkyl. In some embodiments, R₅ is chosen from hydrogen andmethyl.

In some embodiments, R₆ is chosen from optionally substituted alkyl.

In some embodiments, R₆ is chosen from optionally substituted acyl. Insome embodiments, R₆ is chosen from acyl. In some embodiments, R₆ ischosen from acetyl, propionyl, isobutyryl, and pivaloyl.

In some embodiments, R₆ is chosen from optionally substitutedalkoxycarbonyl. In some embodiments, R₆ is chosen from alkoxycarbonyl.In some embodiments, R₆ is chosen from optionally substitutedmethoxycarbonyl, ethoxycarbonyl, and isopropoxycarbonyl,

In some embodiments, R₆ is chosen from —P(═O)(OR₇)(OR₈), where R₇ and R₈are independently chosen from hydrogen and optionally substituted alkyl.In some embodiments, R₇ and R₈ are independently chosen from hydrogenand lower alkyl. In some embodiments. R₆ is —P(═O)(OH)(OH).

In some embodiments, the compound of Formula III is chosen fromcompounds III-a-III-f.

The chemical entities described herein may exhibit increased solubilityas compared with bufalin. The solubility of the chemical entitiesdescribed herein in can be tested as described below. Certain of thechemical entities described herein displayed a solubility of at leasttwice that of bufalin when tested under such conditions. Certain of thechemical entities described herein displayed a solubility of at leastfive times that of bufalin when tested under such conditions. Certain ofthe chemical entities described herein displayed a solubility of atleast ten times that of bufalin when tested under such conditions.

The chemical entities described herein can be synthesized utilizingtechniques well known in the art from commercially available startingmaterials and reagents. For example, the chemical entities describedherein can be prepared as illustrated below with reference to theexamples and reaction schemes.

Bufalin can be obtained from the skin glands of Bufo gargarizans or B.melanostictus toads and is commercially available, e.g. fromSigma-Aldrich Corp. (St. Louis, Mo.). Other reagents are commerciallyavailable, e.g. from Sigma-Aldrich Corp., or can be readily prepared bythose skilled in the art using commonly employed synthetic methodology.

Generally, compounds of Formula I can be prepared from bufalin throughactivated esters. Compounds of Formula II can be prepared from bufalinby standard acylation/esterification procedures. In one approach,esterification is accomplished by reaction of bufalin with the acid inthe presence of coupling agent such as DCC, EDC, or HBTU. Compounds ofFormula III can be prepared from bufalin by standard alkylation/etherformation procedures. The desired product can be purified from thereaction mixture by standard methods, e.g. by extraction and/or silicagel chromatography or high-pressure liquid chromatography.

The chemical entities described herein may be prepared in substantiallypure form, typically by standard chromatographic methods, prior toformulation in a pharmaceutically acceptable form.

The chemical entities described herein may be used in treating a varietyof cancers. Cancers that can be prevented and/or treated by the chemicalentities, compositions, and methods described herein include, but arenot limited to, human sarcomas and carcinomas, e.g. carcinomas, e.g.,colon carcinoma, pancreatic cancer, breast cancer, ovarian cancer,prostate cancer, fibrosarcoma, myxosarcoma, liposarcoma, chondrosarcoma,osteogenic sarcoma, chondroma, angiosarcoma, endotheliosarcoma,lymphangiosarcoma, lymphangioendotheliosarcoma, synovioma, mesothelioma,Ewing's tumor, leiomyosarcoma, rhabdomyosarcoma, squamous cellcarcinoma, basal cell carcinoma, adenocarcinoma, sweat gland carcinoma,sebaceous gland carcinoma, papillary carcinoma, papillaryadenocarcinomas, cystadenocarcinoma, medullary carcinoma, bronchogeniccarcinoma, renal cell carcinoma, hepatoma, bile duct carcinoma,choriocarcinoma, seminoma, embryonal carcinoma, Wiims' tumor, cervicalcancer, testicular tumor, lung carcinoma, small cell lung carcinoma,bladder carcinoma, epithelial carcinoma, glioma, astrocytoma,medulloblastoma, craniopharyngioma, ependymoma, pinealoma,hemangioblastoma, acoustic neuroma, oligodendroglioma, meningioma,melanoma, neuroblastoma, retinoblastoma, leukemias, e.g., acutelymphocytic leukemia and acute myelocytic leukemia (mycloblastic,promyelocytic, myelomonocytic, monocytic and erythroleukemia); chronicleukemia (chronic myelocytic (granulocytic) leukemia and chroniclymphocytic leukemia); and polycythemia vera, lymphoma (Hodgkin'sdisease and non-Hodgkin's disease), multiple myeloma, Waldenstrom'smacroglobulinemia, and heavy chain disease.

In some embodiments, the chemical entities described herein are used forthe treatment of cancers of the

(i) digestive system including, without limitation, the esophagus,stomach, small intestine, colon (including colorectal), liver &intrahepatic bile duct, gallbladder & other biliary, pancreas, and otherdigestive organs;

(ii) respiratory system, including without limitation, larynx, lung &bronchus, and other respiratory organs;

(iii) breast;

(iv) genital system, including without limitation, uterine cervix,ovary, and prostate;

(v) urinary system, including without limitation, urinary bladder andkidney and renal pelvis; and

(vi) oral cavity & pharynx, including without limitation, tongue, mouth,pharynx, and other oral cavity.

In some embodiments, the chemical entities described herein are used forthe treatment of colorectal cancer, liver cancer, lung cancer, breastcancer and oral cancer.

Chemical entities described herein having the desired pharmacologicalactivity may be administered, in some embodiments, as a pharmaceuticallyacceptable composition comprising an pharmaceutical excipient, to apatient, as described herein. Depending upon the manner of introduction,the chemical entities may be formulated in a variety of ways asdiscussed below. The concentration of the at least one chemical entityin the formulation may vary from about 0.01-100 wt. %.

The administration of the chemical entities described herein can be donein a variety of ways, including, but not limited to, orally,subcutaneously, intravenously, intranasally, transdermally,intraperitoneally, intramuscularly, intrapulmonary, vaginally, rectally,or intraocularly.

Pharmaceutical dosage forms include at least one chemical entitydescribed herein and one or more pharmaceutical excipients. As is knownin the art, pharmaceutical excipients are secondary ingredients whichfunction to enable or enhance the delivery of a drug or medicine in avariety of dosage forms (e.g.: oral forms such as tablets, capsules, andliquids; topical forms such as dermal, ophthalmic, and otic forms;suppositories; injectables; respiratory forms and the like).Pharmaceutical excipients include inert or inactive ingredients,synergists or chemicals that substantively contribute to the medicinaleffects of the active ingredient. For example, pharmaceutical excipientsmay function to improve flow characteristics, product uniformity,stability, taste, or appearance, to ease handling and administration ofdose, for convenience of use, or to control bioavailability. Whilepharmaceutical excipients are commonly described as being inert orinactive, it is appreciated in the art that there is a relationshipbetween the properties of the pharmaceutical excipients and the dosageforms containing them.

Pharmaceutical excipients suitable for use as carriers or diluents arewell known in the art, and may be used in a variety of formulations.See, e.g., Remington's Pharmaceutical Sciences, 18th Edition, A. R.Gennaro, Editor, Mack Publishing Company (1990); Remington: The Scienceand Practice of Pharmacy, 21^(st) Edition, Lippincott Williams & Wilkins(2005); Handbook of Pharmaceutical Excipients, 3rd Edition, A. H. Kibbe,Editor, American Pharmaceutical Association, and Pharmaceutical Press(2000); and Handbook of Pharmaceutical Additives, compiled by Michaeland Irene Ash, Gower (1995), each of which is incorporated herein byreference for all purposes.

Oral solid dosage forms such as tablets will typically comprise one ormore pharmaceutical excipients, which may for example help impartsatisfactory processing and compression characteristics, or provideadditional desirable physical characteristics to the tablet. Suchpharmaceutical excipients may be selected from diluents, binders,glidants, lubricants, disintegrants, colors, flavors, sweetening agents,polymers, waxes or other solubility-retarding materials.

Compositions for intravenous administration will generally compriseintravenous fluids, i.e., sterile solutions of simple chemicals such assugars, amino acids or electrolytes, which can be easily carried by thecirculatory system and assimilated.

Dosage forms for parenteral administration will generally comprisefluids, particularly intravenous fluids, i.e., sterile solutions ofsimple chemicals such as sugars, amino acids or electrolytes, which canbe easily carried by the circulatory system and assimilated. Such fluidsare typically prepared with water for injection USP. Fluids usedcommonly for intravenous (IV) use are disclosed in Remington: TheScience and Practice of Pharmacy, Lippincott Williams & Wilkins (2005).The pH of such IV fluids may vary, and will typically be from 3.5 to 8as known in the art.

The chemical entities described herein may also be used in conjunctionwith other well known therapeutic agents that are selected for theirparticular usefulness against the condition that is being treated. Forexample, the chemical entities described herein may be useful incombination with at least one additional anti-cancer and/or cytotoxicagents. Further, the chemical entities described herein may also beuseful in combination with other inhibitors of parts of the signalingpathway that links cell surface growth factor receptors to nuclearsignals initiating cellular proliferation.

Such known anti-cancer and/or cytotoxic agents that may be used incombination with the chemical entities described herein include:

(i) other antiproliferative/antineoplastic drugs and combinationsthereof, as used in medical oncology, such as alkylating agents (forexample cis-platin, oxaliplatin, carboplatin, cyclophosphamide, nitrogenmustard, melphalan, chlorambucil, busulphan, temozolamide andnitrosoureas); antimetabolites (for example gemcitabine and antifolatessuch as fluoropyrimidines like 5-fluorouracil and tegafur, raltitrexed,methotrexate, cytosine arabinoside, and hydroxyurea); antitumorantibiotics (for example anthracyclines like adriamycin, bleomycin,doxorubicin, daunomycin, epirubicin, idarubicin, mitomycinC,dactinomycin and mithramycin); antimitotic agents (for example vincaalkaloids like vincristine, vinblastine, vindesine and vinorelbine andtaxoids like taxol and taxotere and polokinase inhibitors); andtopoisomerase inhibitors (for example epipodophyllotoxins like etoposideand teniposide, amsacrine, topotecan and camptothecin);

(ii) cytostatic agents such as antioestrogens (for example tamoxifen,fulvestrant, toremifene, raloxifene, droloxifene and iodoxyfene),antiandrogens (for example bicalutamide, flutamide, nilutamide andcyproterone acetate), LHRH antagonists or LHRH agonists (for examplegoserelin, leuprorelin and buserelin), progestogens (for examplemegestrol acetate), aromatase inhibitors (for example as anastrozole,letrozole, vorazole and exemestane) and inhibitors of 5a-reductase suchas finasteride;

(iii) anti-invasion agents [for example c-Src kinase family inhibitorslike4-(6-chloro-2,3methylenedioxyanilino)-7-[2-(4-methylpiperazin-1-yl)ethoxy]-5-tetrahydropyran-4yloxyquinazoline(AZD0530; International Patent Application WO 01/94341),N-(2-chloro-6-methylphenyl)-2-{6-[4-(2-hydroxyethyl)piperazin-1-yl]-2-methylpyrimidin-4ylamino}thiazole-5-carboxamide(dasatinib, BMS-354825; J. Med. Chem., 2004, 47, 66586661) and bosutinib(SK1-606), and metalloproteinase inhibitors like marimastat, inhibitorsof urokinase plasminogen activator receptor function or antibodies toHeparanase];

(iv) inhibitors of growth factor function: for example such inhibitorsinclude growth factor antibodies and growth factor receptor antibodies(for example the anti-erbB2 antibody trastuzumab [Herceptin™], theanti-EGFR antibody panitumumab, the anti-erbB 1 antibody cetuximab[Erbitux, C225] and any growth factor or growth factor receptorantibodies disclosed by Stem et al. Critical reviews inoncology/haematology, 2005, Vol. 54, pp 11-29); such inhibitors alsoinclude tyrosine kinase inhibitors, for example inhibitors of theepidermal growth factor family (for example EGFR family tyrosine kinaseinhibitors such asN-(3-chloro-4-fluorophenyl)-7-methoxy-6-(3-morpholinopropoxy)quinazolin-4-amine(gefitinib, ZD1839),N-(3-ethynylphenyl)-6,7-bis(2-methoxyethoxy)quinazolin-4-amine(erlotinib, OSI-774) and6-acrylamido-N-(3-chloro-4-fluorophenyl)-7-(3-morpholinopropoxy)-quinazolin-4-amine(CI 1033), erbB2 tyrosine kinase inhibitors such as lapatinib);inhibitors of the hepatocyte growth factor family; inhibitors of theinsulin growth factor family; inhibitors of the platelet-derived growthfactor family such as imatinib and/or nilotinib (AMN107); inhibitors ofserine/threonine kinases (for example Ras/Raf signalling inhibitors suchas farnesyl transferase inhibitors, for example sorafenib (BAY 43-9006),tipifarnib (RI15777) and lonafarnib (SCH66336)), inhibitors of cellsignalling through MEK and/or AKT kinases, c-kit inhibitors, abl kinaseinhibitors, P13 kinase inhibitors, Plt3 kinase inhibitors, CSF-IR kinaseinhibitors, IGF receptor (insulin like growth factor) kinase inhibitors;aurora kinase inhibitors (for example AZD1152, PH739358, VX-680,MLN8054, R763, MP235, MP529, VX-528 and AX39459) and cyclin dependentkinase inhibitors such as CDK2 and/or CDK4 inhibitors;

(v) antiangiogenic agents such as those which inhibit the effects ofvascular endothelial growth factor, [for example the anti-vascularendothelial cell growth factor antibody bevacizumab (Avastin™) and forexample, a VEGF receptor tyrosine kinase inhibitor such as vandetanib(ZD6474), vatalanib (PTK787), sunitinib (SU11248), axitinib (AG-013736),pazopanib (GW 786034) and4-{4-fluoro-2-methylindol-5-yloxy)-6-methoxy-7-(3pyrrolidin-1-ylpropoxy)quinazoline(AZD2171; Example 240 within WO 00/47212), compounds such as thosedisclosed in International Patent Applications WO 97/22596, WO 97/30035,WO 97/32856 and WO 98/13354 and compounds that work by other mechanisms(for example linomide, inhibitors of integrin av˜3 function andangiostatin));

(vi) vascular damaging agents such as Combretastatin A4 and compoundsdisclosed in International Patent Applications WO 99/02166, WO 00/40529,WO 00/41669, WO 01/92224, WO 02/04434 and WO 02/08213;

(vii) an endothelin receptor antagonist, for example zibotentan (ZD4054)or atrasentan;

(viii) antisense therapies, for example those which are directed to thetargets listed above, such as ISIS 2503, an anti-ras antisense;

(ix) gene therapy approaches, including for example approaches toreplace aberrant genes such as aberrant p53 or aberrant BRCA1 or BRCA2,GDEPT (gene-directed enzyme pro-drug therapy) approaches such as thoseusing cytosine deaminase, thymidine kinase or a bacterial nitroreductaseenzyme and approaches to increase subject tolerance to chemotherapy orradiotherapy such as multi-drug resistance gene therapy; and

(x) immunotherapy approaches, including for example ex-vivo and in-vivoapproaches to increase the immunogenicity of subject's tumor cells, suchas transfection with cytokines such as interleukin 2, interleukin 4 orgranulocyte-macrophage colony stimulating factor, approaches to decreaseT-cell anergy, approaches using transfected immune cells such ascytokine-transfected dendritic cells, approaches usingcytokine-transfected tumor cell lines and approaches usinganti-idiotypic antibodies.

In certain embodiments, the at least one chemical entity is administeredin combination with one or more agents chosen from pacliataxel,bortezomib, dacarbazine, gemcitabine, trastuzumab, bevacizumab,capecitabine, docetaxel, erlotinib, aromatase inhibitors, such asAROMASIN™ (exemestane), and estrogen receptor inhibitors, such asFASLODEX™ (fulvestrant).

When a chemical entity described herein is administered into a humansubject, the daily dosage will normally be determined by the prescribingphysician with the dosage generally varying according to the age,weight, and response of the individual subject, as well as the severityof the subject's symptoms.

In one exemplary application, a suitable amount of at least one chemicalentity is administered to a mammal undergoing treatment for cancer, forexample, breast cancer. Administration typically occurs in an amount ofbetween about 0.01 mg/kg of body weight to about 100 mg/kg of bodyweight per day (administered in single or divided doses), such as atleast about 0.1 mg/kg of body weight per day. A particular therapeuticdosage can include, e.g., from about 0.01 mg to about 1000 mg of thechemical entity, such as including, e.g., from about 1 mg to about 1000mg. The quantity of the at least one chemical entity in a unit dose ofpreparation may be varied or adjusted from about 0.1 mg to 1000 mg, suchas from about 1 mg to 300 mg, for example 10 mg to 200 mg, according tothe particular application. The amount administered will vary dependingon the particular IC₅₀ value of the at least one chemical entity usedand the judgment of the attending clinician taking into considerationfactors such as health, weight, and age. In combinational applicationsin which the at least one chemical entity described herein is not thesole active ingredient, it may be possible to administer lesser amountsof the at least one chemical entity and still have therapeutic orprophylactic effect.

In some embodiments, the pharmaceutical preparation is in unit dosageform. In such form, the preparation is subdivided into unit dosescontaining appropriate quantities of the active component, e.g., aneffective amount to achieve the desired purpose.

The actual dosage employed may be varied depending upon the requirementsof the subject and the severity of the condition being treated.Determination of the proper dosage for a particular situation is withinthe skill of the art. Generally, treatment is initiated with smallerdosages which are less than the optimum dose of the at least onechemical entity. Thereafter, the dosage is increased by small amountsuntil the optimum effect under the circumstances is reached. Forconvenience, the total daily dosage may be divided and administered inportions during the day if desired.

The amount and frequency of administration of the at least one chemicalentities described herein, and if applicable other chemotherapeuticagents and/or radiation therapy, will be regulated according to thejudgment of the attending clinician (physician) considering such factorsas age, condition and size of the subject as well as severity of thedisease being treated.

The chemotherapeutic agent and/or radiation therapy can be administeredaccording to therapeutic protocols well known in the art. It will beapparent to those skilled in the art that the administration of thechemotherapeutic agent and/or radiation therapy can be varied dependingon the disease being treated and the known effects of thechemotherapeutic agent and/or radiation therapy on that disease. Also,in accordance with the knowledge of the skilled clinician, thetherapeutic protocols (e.g., dosage amounts and times of administration)can be varied in view of the observed effects of the administeredtherapeutic agents (i.e., antineoplastic agent or radiation) on thesubject, and in view of the observed responses of the disease to theadministered therapeutic agents.

Also, in general, the at least one chemical entities described hereinneed not be administered in the same pharmaceutical composition as achemotherapeutic agent, and may, because of different physical andchemical characteristics, be administered by a different route. Forexample, the chemical entities/compositions may be administered orallyto generate and maintain good blood levels thereof, while thechemotherapeutic agent may be administered intravenously. Thedetermination of the mode of administration and the advisability ofadministration, where possible, in the same pharmaceutical composition,is well within the knowledge of the skilled clinician. The initialadministration can be made according to established protocols known inthe art, and then, based upon the observed effects, the dosage, modes ofadministration and times of administration can be modified by theskilled clinician.

The particular choice of chemical entity (and where appropriate,chemotherapeutic agent and/or radiation) will depend upon the diagnosisof the attending physicians and their judgment of the condition of thesubject and the appropriate treatment protocol.

The chemical entities described herein (and where appropriatechemotherapeutic agent and/or radiation) may be administeredconcurrently (e.g., simultaneously, essentially simultaneously or withinthe same treatment protocol) or sequentially, depending upon the natureof the proliferative disease, the condition of the subject, and theactual choice of chemotherapeutic agent and/or radiation to beadministered in conjunction (i.e., within a single treatment protocol)with the chemical entity/composition.

In combinational applications and uses, the chemical entity/compositionand the chemotherapeutic agent and/or radiation need not be administeredsimultaneously or essentially simultaneously, and the initial order ofadministration of the chemical entity/composition, and thechemotherapeutic agent and/or radiation, may not be important. Thus, theat least one chemical entity described herein may be administered firstfollowed by the administration of the chemotherapeutic agent and/orradiation; or the chemotherapeutic agent and/or radiation may beadministered first followed by the administration of the at least onechemical entity described herein. This alternate administration may berepeated during a single treatment protocol. The determination of theorder of administration, and the number of repetitions of administrationof each therapeutic agent during a treatment protocol, is well withinthe knowledge of the skilled physician after evaluation of the diseasebeing treated and the condition of the subject. For example, thechemotherapeutic agent and/or radiation may be administered first, andthen the treatment continued with the administration of the at least onechemical entity described herein followed, where determinedadvantageous, by the administration of the chemotherapeutic agent and/orradiation, and so on until the treatment protocol is complete.

Thus, in accordance with experience and knowledge, the practicingphysician can modify each protocol for the administration of a chemicalentity/composition for treatment according to the individual subject'sneeds, as the treatment proceeds.

The attending clinician, in judging whether treatment is effective atthe dosage administered, will consider the general well-being of thesubject as well as more definite signs such as relief of disease-relatedsymptoms, inhibition of tumor growth, actual shrinkage of the tumor, orinhibition of metastasis. Size of the tumor can be measured by standardmethods such as radiological studies, e.g., CAT or MRI scan, andsuccessive measurements can be used to judge whether or not growth ofthe tumor has been retarded or even reversed. Relief of disease-relatedsymptoms such as pain, and improvement in overall condition can also beused to help judge effectiveness of treatment.

EXAMPLES

The following examples serve to more fully describe the manner of usingthe invention. These examples are presented for illustrative purposesand should not serve to limit the true scope of the invention.

In carrying out the procedures of the methods described herein, it is ofcourse to be understood that reference to particular buffers, media,reagents, cells, culture conditions and the like are not intended to belimiting, but are to be read so as to include all related materials thatone of ordinary skill in the art would recognize as being of interest orvalue in the particular context in which that discussion is presented.For example, it is often possible to substitute one buffer system orculture medium for another and still achieve similar, if not identical,results. Those of skill in the art will have sufficient knowledge ofsuch systems and methodologies so as to be able, without undueexperimentation, to make such substitutions as will optimally servetheir purposes in using the methods and procedures disclosed herein.

Example I: Preparation of(R)-(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl2-aminopropanoate

To a solution of Boc-amino acid (11.3 mg, 0.06 mmol, 1.2 eq), HOBT (9.7mg, 0.072 mmol. 1.44 eq), EDC (13.8 mg, 0.072 mmol, 1.44 eq) and DMAP(16.8 mg, 0.15 mmol, 3 eq) in CH₂Cl₂ was added bufalin (20 mg, 0.05mmol). The mixture was stirred at 37° C. for 16 h and then purified viapreparative TLC (PE/EA=1:1) to afford(R)-(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl2-((tert-butoxycarbonyl)amino)propanoate (23 mg, 79.8%).

To a solution of(R)-(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl2-((tert-butoxycarbonyl)amino)propanoate in EtOAc (3 mL) was added HCl(4 M in EtOAc, 3 mL) in drops at 0° C. The resulting mixture was warmedto rt after 30 min and stirred for 2 h. The mixture was quenched withsaturated NaHCO₃ solution and extracted with EtOAc (20 mL×3). Theorganic layer was washed with H₂O (10 mL×4) and then dried overanhydrous Na₂SO₄, concentrated under reduced pressure. The crude productwas then purified via Prep-TLC (CH₂Cl₂: MeOH=10:1) to afford the(R)-(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl 2-aminopropanoate (8 mg,43% yield) as a white solid. LRMS (M+H⁺) m/z 458.5. ¹H NMR (CD₃OD, 400MHz) δ 7.89 (dd, J=9.6, 2.4 Hz, 1H), 7.33 (m, 1H), 6.17 (d, J=9.6 Hz,1H), 5.02 (m, 1H), 3.54 (m, 1H), 2.43-2.48 (m, 1H), 1.08-2.15 (m, 24H),0.88 (s, 3H), 0.62 (s, 3H).

Example II: Preparation of(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl(2-(pyrrolidin-1-yl)ethyl) carbonate

To a solution of 1 (60 mg, 0.15 mmol), and DMAP (16.8 mg, 0.15 mmol) inCH₂Cl₂ (10 mL) was added DIEA (77.4 mg, 0.6 mmol) and 4-nitrophenylcarbonochloridate (60.6 mg, 0.3 mmol). The mixture was stirred at 37° C.for 16 h and then purified via preparative TLC (PE/EA=1:1) to afford(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl4-nitrophenyl carbonate as a white solid (72 mg, 87.1%).

To a solution of(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl4-nitrophenyl carbonate (24 mg, 0.044 mmol) in CH₂Cl₂ was added2-(pyrrolidin-1-yl)ethanol (50.6 mg, 0.44 mmol, 10 eq), DIEA (22.7 mg,0.176 mmol, 4 eq) and DMAP (19.7 mg, 0.176 mmol, 4 eq). The resultantmixture was stirred at 40° C. for 16 h and then purified via preparativeTLC to afford(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl2-(pyrrolidin-1-yl)ethyl carbonate (20 mg, 87.0%) as a white solid. LRMS(M m/z 528.4. ¹H NMR (CD₃OD, 400 MHz) δ 8.01 (dd, J=10.0, 2.4 Hz, 1H),7.44 (m, 1H), 6.29 (d, J=10.0 Hz, 1H), 5.00 (m, 1H), 4.35 (t, J=5.4 Hz,2H), 3.12 (m, 2H), 2.96 (m, 4H), 2.55-2.60 (m, 1H), 1.08-2.15 (m, 25H),0.99 (s, 3H), 0.73 (s, 3H).

Example III: Preparation of4-(((((3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl)oxy)carbonyl)amino)butanoicacid

To a solution of(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl4-nitrophenyl carbonate (20 mg, 0.036 mmol) in CH₂Cl₂ was added4-aminobutanoic acid (37.1 mg, 0.36 mmol, 10 eq), DIEA (18.6 mg, 0.144mmol, 4 eq) and DMAP (16.1 mg, 0.144 mmol, 4 eq). The resultant mixturewas stirred at 40° C. for 16 h and then purified via preparative TLC toafford4-(((3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yloxy)carbonylamino)butanoicacid (10 mg, 53.5%) as a white solid. LRMS (M−H⁺) m/z 514.4. ¹H NMR(CD₃OD, 400 MHz) δ 7.89 (dd, J=9.6, 2.4 Hz, 1H), 7.33 (m, 1H). 6.18 (d,J=9.6 Hz, 1H), 4.82 (m, 1H), 3.03 (m, 2H), 2.44-2.48 (m, 1H), 1.08-2.15(m, 25H), 0.87 (s, 3H), 0.62 (s, 3H).

Example IV: Preparation of(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl(2-(pyrrolidin-1-yl)ethyl)carbamate

To a solution of(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl4-nitrophenyl carbonate (29 mg, 0.054 mmol) in CH₂Cl₂ was added2-(pyrrolidin-1-yl)ethanamine (61.6 mg, 0.54 mmol). The resultantmixture was stirred at rt for 16 h and then purified via preparative TLCto afford(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl(2-(pyrrolidin-1-yl)ethyl)carbamate (21 mg, 75%) as a white solid. LRMS(M+H⁺) m/z 527.5. ¹H NMR (CD₃OD, 400 MHz) δ 7.89 (dd, J=9.6, 2.4 Hz,1H), 7.33 (m, 1H), 6.18 (d, J 9.6 Hz, 1H), 4.88 (m, 1H), 3.35 (m, 2H),3.12 (m, 2H), 2.46 (m, 1H), 1.08-2.15 (m, 29H), 0.87 (s, 3H), 0.62 (s,3H).

Example V: Preparation of(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-ylpiperazine-1-carboxylate

To a solution of(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl4-nitrophenyl carbonate (29 mg, 0.054 mmol) in CH₂Cl₂ was addedpiperazine (46.4 mg, 0.54 mmol). The resultant mixture was stirred at rtfor 16 h and then purified via preparative TLC to afford(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-ylpiperazine-1-carboxylate (18.6 mg, 69.2%) as a white solid. LRMS (M+H⁺)m/z 499.5. ¹H NMR (CD₃OD, 400 MHz) δ 7.90 (dd, J=9.6, 2.4 Hz, 1H), 7.33(m, 1H), 6.18 (d, J=9.6 Hz, 1H), 4.89 (m, 1H), 3.41 (m, 4H), 2.77-2.80(m, 4H), 2.44-2.48 (m, 1H), 1.08-2.15 (m, 21H), 0.88 (s, 3H), 0.62 (s,3H).

Example VI: Preparation of(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl(2-morpholinoethyl)carbamate

To a solution of(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl4-nitrophenyl carbonate (29 mg, 0.054 mmol) in CH₂Cl₂ was added2-morpholinoethanamine (70.2 mg, 0.54 mmol). The resultant mixture wasstirred at rt for 16 h and then purified via preparative TLC to afford(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl(2-morpholinoethyl)carbamate (18 mg, 61.4%) as a white solid. LRMS(M+H⁺) m/z 543.4. ¹H NMR (CD₃OD, 400 MHz) δ 7.89 (dd, J=9.6, 2.4 Hz,1H), 7.33 (m, 1H), 6.18 (d, J=9.6 Hz, 1H), 4.82 (m, 1H), 3.59 (m, 4H),3.16 (m, 2H), 2.46 (m, 2H), 2.41 (m, 5H), 1.08-2.15 (m, 21H), 0.87 (s,3H), 0.61 (s, 3H).

Example VII: Additional Compounds

Using methods similar to those described above, the following compoundswere also prepared.

Observed Chemical Name Ion m/z (R)-(3S,5R,8R,9S,10S,13R,14S,17R)-14- M +H⁺ 486.5 hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl 2-amino-3-methylbutanoate(R)-(3S,5R,8R,9S,10S,13R,14S,17R)-14- M + H⁺ 500.6hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl2-amino-4-methylpentanoate (S)-(3S,5R,8R,9S,10S,13R,14S,17R)-14- M + H⁺500.5 hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl2-amino-4-methylpentanoate (3S,5R,8R,9S,10S,13R,14S,17R)-14- M + H⁺544.5 hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl (2-morpholinoethyl)carbonate (S)-(3S,5R,8R,9S,10S,13R,14S,17R)-14- M + H⁺ 458.5hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl 2-aminopropanoate(S)-(3S,5R,8R,9S,10S,13R,14S,17R)-14- M + H⁺ 486.5hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl2-amino-3-methylbutanoate (3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy- M +H⁺ 500.4 10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-ylmorpholine-4-carboxylate

Example VIII: Measurement of Equilibrium Solubility

The equilibrium solubility of compounds is measured in aqueous buffer.Excess amount of solid compound is added into buffer solution and thesample is briefly sonicated and then shaken at rt for 24 h. The sampleis filtered and the concentration is analyzed by HPLC UV. A standardsolution at 0.2 mg/mL was prepared in methanol or acetonitrile for eachcompound and used as an external standard for quantification. Data forbufalin and four of the compounds specifically described herein inNaOAc/AcOH buffer (100 mM, pH 5.0) is shown below.

Solubility Chemical Name (mg/mL) Bufalin 0.041(S)-(3S,5R,8R,9S,10S,13R,14S,17R)-14- 0.12hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren- 3-yl2-amino-3-methylbutanoate (3S,5R,8R,9S,10S,13R,14S,17R)-14- 0.71hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren- 3-yl(2-(pyrrolidin-1-yl)ethyl) carbonate (3S,5R,8R,9S,10S,13R,14S,17R)-14-1.04 hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren- 3-yl(2-(pyrrolidin-1-yl)ethyl)carbamate (3S,5R,8R,9S,10S,13R,14S,17R)-14-0.84 hydroxy-10,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren- 3-ylpiperazine-1-carboxylate

Example IX: Inhibition of Cell Growth in Tumor Cells

Inhibition of cell growth by compounds was measured using MTT assay(Mosmann, T., Journal of Immunological Methods, 1983, 65, 55-63). Tumorcell lines were purchased from ATCC (American Type Culture Collection,Manassas, Va.). All cell lines were maintained in RPMI 1640 (Hyclone)supplemented with 10% fetal bovine serum (FBS, Hyclone), glutamine (2mM, Hyclone), and antibiotics (penicillin 100 U/mL and streptomycin 50μg/mL) at 37° C. in a humidified atmosphere of 5% CO₂ in air. Taxol(positive control, Sigma) and compounds were dissolved in DMSO (Sigma),and the final concentration of DMSO in the medium was 1%. Tumor cellswere plated in 96-well plates at densities from 4000 cells/well of a96-well plate and allowed to adhere/grow for 24 h. They were thentreated with various concentrations of drug for 72 h.3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT,Sigma) was used to determine the number of viable cells at the time ofcompound addition and the number of cells remaining after 72 h compoundexposure. The number of cells remaining after 72 h was compared to thenumber of viable cells at the time of compound addition by measuring theabsorbance at 570 nm, allowing for the calculation of growth inhibition.

All concentrations of compounds were tested in triplicate and controlswere averaged over 4 wells. IC₅₀ was calculated by plotting theconcentration of compound vs the percentage of inhibition in treatedwells using GraphPad Prism 5. Data for bufalin and representativecompounds are shown below.

TABLE I Inhibitory activity of representative compounds in A549 cells.A549 cell Chemical Name IC₅₀ (nM) Bufalin 4.4(R)-(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13- 3.4dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl 2-aminopropanoate(R)-(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13- 147.1dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl 2-amino-3- methylbutanoate(R)-(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13- 58.8dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl 2-amino-4- methylpentanoate(S)-(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13- 15.1dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl 2-amino-4- methylpentanoate(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13- 12.2dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl (2- morpholinoethyl) carbonate(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13- 2.8dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl (2-(pyrrolidin- 1-yl)ethyl)carbamate(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13- 7.4dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadeca-hydro-1H-cyclopenta[a]phenanthren-3-yl(2-morpholino- ethyl)-carbamate(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13- 1.8dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadeca-hydro-1H-cyclopenta[a]phenanthren-3-yl piperazine-1- carboxylate4-(((((3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy- 60.010,13-dimethyl-17-(2-oxo-2H-pyran-5-yl)-hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl)- oxy)carbonyl)amino)butanoic acid

TABLE II Inhibitory activity of representative compounds in Bcap-37cells. Bcap-37 cell Chemical Name IC50 (nM) Bufalin 14.0(S)-(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13- 15.9dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl 2-aminopropanoate(S)-(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13- 48.9dimethyl-17-(2-oxo-2H-pyran-5-yl)hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl 2-amino-3- methylbutanoate(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13- 10.6dimethyl-17-(2-oxo-2H-pyran-5-yl)-hexadecahydro-1H-cyclopenta[a]phenanthren-3-yl (2-(pyrrolidin- 1-yl)ethyl) carbonate(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13- 5.3dimethyl-17-(2-oxo-2H-pyran-5-yl)hexa-decahydro-1H-cyclopenta[a]phenanthren-3-yl (2-(pyrrolidin- 1-yl)ethyl)carbamate(3S,5R,8R,9S,10S,13R,14S,17R)-14-hydroxy-10,13- 223.0dimethyl-17-(2-oxo-2H-pyran-5-yl)hexa-decahydro-1H-cyclopenta[a]phenanthren-3-yl morpholine-4- carboxylate

Example X: Inhibition of Tumor Growth in Xenograft Model

Cells were implanted in BALB/c female nude mice and grown as tumorxenografts. When tumors achieved 150-200 mm³, mice were assigned intotreatment and control groups using randomized block design based upontheir tumor volumes. Each group contained 10 tumor-bearing mice. Tumorswere measured twice weekly in two dimensions using a caliper, and thetumor volume was calculated from two-dimensional measurements using theequation V=0.5×a×b² where a and b are the long and short diameters ofthe tumor, respectively. The tumor volume was then used for calculationsof T/C values. The T/C value was an indication of antitumoreffectiveness; T and C were the mean volume of the treated and controlgroups, respectively, on a given day. Data for one of the compoundsspecifically described in Example IX is shown below.

Tumor Tumor Volume Volume Pre- Post- Dose Sched- treatment treatment(mg/kg) ule Route (mm³) (mm³) T/C Vehicle — QDX10 i.v. 151 ± 12 524 ± 53— Compound 3 QDX10 i.v. 151 ± 12 261 ± 26 49.8% Paclitaxel 10 Q4DX3 i.v.152 ± 13 391 ± 43 74.6%

While some embodiments have been shown and described, variousmodifications and substitutions may be made thereto without departingfrom the spirit and scope of the invention. For example, for claimconstruction purposes, it is not intended that the claims set forthhereinafter be construed in any way narrower than the literal languagethereof, and it is thus not intended that exemplary embodiments from thespecification be read into the claims. Accordingly, it is to beunderstood that the present invention has been described by way ofillustration and not limitations on the scope of the claims.

1-31. (canceled)
 32. A method of treating cancer in a subject, themethod comprising administering to the subject in need thereof atherapeutically effective amount of a compound of Formula III:

or a pharmaceutically acceptable salt thereof, wherein: R₅ is chosenfrom hydrogen, optionally substituted alkyl, optionally substitutedcycloalkyl, optionally substituted heterocycloalkyl, optionallysubstituted aryl, and optionally substituted heteroaryl; and R₆ ischosen from optionally substituted alkyl, optionally substitutedcycloalkyl, optionally substituted heterocycloalkyl, optionallysubstituted aryl, optionally substituted heteroaryl, optionallysubstituted acyl, optionally substituted alkoxycarbonyl, and—P(═O)(OR₇)(OR₈), where R₇ and R₈ are independently chosen from hydrogenand optionally substituted alkyl; wherein the cancer is selected fromthe group consisting of colorectal cancer, liver cancer, lung cancer,breast cancer, prostate cancer, pancreatic cancer, brain cancer, andoral cancer.
 33. The method of claim 32, wherein the subject is a human.34. The method of claim 32, wherein the compound or the pharmaceuticallyacceptable salt is administered orally, subcutaneously, intravenously,intranasally, transdermally, intraperitoneally, intramuscularly,intrapulmonary, vaginally, rectally, or intraocularly.
 35. The method ofclaim 32, wherein the compound or the pharmaceutically acceptable saltis administered intravenously.
 36. The method of claim 32, wherein thecompound or the pharmaceutically acceptable salt is administered orally.37. The method of claim 32, further comprising administering to thesubject an additional anti-cancer and/or cytotoxic agent.
 38. The methodof claim 37, wherein the additional anti-cancer and/or cytotoxic agentis administered simultaneously with the compound or the pharmaceuticallyacceptable salt.
 39. The method of claim 32, wherein the amount of thecompound or the pharmaceutically acceptable salt administered is in therange of 0.01 mg to 100 mg per kilogram body weight of the subject. 40.The method of claim 32, wherein the amount of the compound of FormulaIII administered is in the range of about 0.01 mg to 1000 mg.
 41. Themethod of claim 32, wherein R₅ is hydrogen or an optionally substitutedlower alkyl.
 42. The method of claim 32, wherein R₅ is hydrogen ormethyl.
 43. The method of claim 32, wherein R₆ is an optionallysubstituted alkyl.
 44. The method of claim 32, wherein R₆ is anoptionally substituted acyl.
 45. The method of claim 44, wherein R₆ ischosen from acetyl, propionyl, isobutyryl, and pivaloyl.
 46. The methodof claim 32, wherein R₆ is an optionally substituted alkoxycarbonyl. 47.The method of claim 46, wherein R₆ is chosen from optionally substitutedmethoxycarbonyl, ethoxycarbonyl, and isopropoxycarbonyl.
 48. The methodof claim 32, wherein R₆ is —P(═O)(OR₇)(OR₈), where R₇ and R₈ areindependently chosen from hydrogen and optionally substituted alkyl. 49.The method of claim 48, wherein R₆ is —P(═O)(OH)(OH).
 50. The method ofclaim 32, wherein the compound is chosen from the group consisting of:


51. The method of claim 32, wherein the cancer is lung cancer.
 52. Themethod of claim 32, wherein the cancer is breast cancer.